Patent application WO 99/21707 discloses a laminate having at least one glass layer as a constituting layer, the glass layer having a thickness of less than 4 mm. Such a laminate presents several advantages over e.g. transparent polymer layers, such as a high thermal stability, a high physical density, high hardness, very good resistance to chemicals, good barrier properties against moisture, solvents and oxygen. Moreover, glass has a high transparency and good optical characteristics.
However, a problem of such a laminate is its limited flexibility. Due to the brittleness of glass, the laminate cannot be deformed to a considerable extent, especially if the glass has a rather large thickness, e.g. larger than 1 mm, or if the deformed glass has a small radius of curvature. Even very thin, and hence flexible glass layers may break.
It would be advantageous to use such a glass laminate for the production of security cards. Because of the high physical density of glass, an original security card comprising a glass laminate can be distinguished from a counterfeited plastic card, by measuring the density of the card. However, a security card comprising such a glass laminate may break easily, e.g. when put away in a wallet in a trouser pocket.
It would also be advantageous to use such a glass laminate for making photomasks, that can e.g. be used to manufacture printed circuit boards, semiconductor devices, integrated circuits. Prior art masks having a polymer support suffer from insufficient dimensional stability, due to environmental changes in temperature and/or humidity. A glass layer support provides the important advantage of a high dimensional stability. However, a photomask comprising such a glass laminate may break e.g. during manipulation, due to its low flexibility.